An anesthesia machine, which is an equipment very demanding for security, stability and operability used in the operating room, is applicable to deliver an anesthetic into pulmonary alveoli of a patient via a mechanical circuit and form a partial pressure of anesthetic gas in the pulmonary alveoli. The anesthetic has a direct inhibition action on the central nervous system after being diffused into blood, resulting in an effect of general anesthesia. The anesthesia machine preliminarily includes four parts of a gas supply system, a vaporizer, a ventilator and a circuit system.
The anesthetic evaporator, as a vital component in the anesthesia machine, is introduced to the anesthesia machine to provide the patient with a stable anesthetic gas mixture of an accurate concentration. The anesthetic evaporator can effectively evaporate the anesthetic, and also accurately control the concentration of the outputted anesthetic vapor.
The anesthetic evaporator is incorporated into the anesthesia machine through a bypass valve. When the anesthetic evaporator is not connected, the anesthesia machine delivers gas to the patient via the bypass valve, in this case, the bypass valve functions as a passage for transmitting the gas, and therefore should be leakage-proof to prevent the leakage of the gas. Poor gas tightness of the bypass valve may cause the leakage of a part of the gas, thus resulting in a waste of resources. Meanwhile, it should be ensured that the gas flowing through the bypass valve does not encounter gas resistance or encounters little gas resistance, thus providing smoothly the patient with the gas. When the anesthetic evaporator is connected, a gas passage within the bypass valve is closed, all the gas flows through the anesthetic evaporator, enters again into the anesthesia machine via the bypass valve after being outputted by the evaporator, and then is delivered to the patient. In this case, the bypass valve should be leakage-proof to prevent the leakage of the anesthetic. Poor gas tightness of the bypass valve may cause the leakage of the anesthetic, causing not only a waste of resources, but also an anesthesia to doctors, which has a great impact on the surgery quality and patient safety.
Traditional bypass valve includes a gas inlet and a gas outlet. In use, the gas from the gas inlet enters into the evaporator via the bypass valve, flows to the downstream of the anesthesia machine through the gas outlet of the bypass valve after being outputted by the evaporator, and then is delivered to the patient. In practice, a gas backflow occurs to the bypass valve in the case of pressure fluctuation at the gas outlet, resulting in a concentration of the outputted anesthetic gas that is not precise enough to be used conveniently; meanwhile, the traditional bypass valve has still defects such as a structural and technological defect, poor gas tightness, and so on.